Viral hepatitis

Hepatitis is an inflammation of the liver. It may be acute or chronic, in which case it can develop into liver disease (sclerosis of the liver) or cancer. The liver produces substances that are essential to sustaining life (blood coagulation factors, for example) and eliminates toxins from a number of substances.
Hepatitis may be caused by a virus (hepatitis A, B, C, D and E viruses; a Herpes virus; yellow fever virus, etc.), alcoholism, medicines, etc.

Impact on public health

Hepatitis B caused more than 100,000 deaths worldwide in 2003, in addition to which a further 300,000 deaths are due to liver cancer, to which hepatitis B contributes (responsible for approximately half of liver cancers). Hepatitis C caused more than 50,000 deaths and contributed to 175,000 deaths due to liver cancer.
It is estimated that worldwide there are around 350 million carriers of the hepatitis B virus, which is transmitted through blood and sexual contact. In emerging countries, maternal-fetal contamination is the most common source of transmission. Screening for hepatitis B (as well as C) during blood donations has helped limit the spread of these viruses. The utilization of condoms during sexual relations limits the risk of transmission of the hepatitis B and C viruses. Immunization with the hepatitis B vaccine provides effective protection against infection, however the countries that are most affected by the epidemic do not always have the means to finance immunization programs. The World Health Organisation (WHO) has set up a Hepatitis B vaccination program in emerging countries. The vaccine to prevent hepatitis A may be given to people in high-risk populations (frequent travelers, etc.)

Diagnosis

·Clinical signs: symptoms may or may not be present. Often they are non-specific: fatigue, headache, loss of appetite, nausea, abdominal or joint pain, fever, skin outbreak. Jaundice is present in less than 20% of cases of viral A, B, C, D and E hepatitis and in around 5% of cases of hepatitis caused by the infectious mononucleosis virus.
·Additional examinations: Ultrasound of the liver is not always useful. It may make it possible to measure the effects on the liver. A liver biopsy may be used to confirm the diagnosis of chronic hepatitis.
·Biological analyses: These may be used to elucidate signs (of variable intensity) of the effect on the liver (increased hepatic enzyme levels in the blood, such as transaminases and others). The results of virological examinations (viral antibodies using serology, detection of the virus itself using molecular biology) make it possible to confirm a diagnosis of viral hepatitis and can determine which virus is responsible, the onset of infection and, in certain cases, give indications as to how the condition will develop in the medium term. For example, viral hepatitis A never develops into chronic hepatitis, unlike hepatitis B (5% of cases in adults), and hepatitis C (80% of adult cases).